Electrochemical method has been used to study the interaction between DNA and the compound N-(3',6'-dihydroxy-3-oxospiro[isobenzofuran-1(3H),9'-[9H]xanthen]-5-yl)-N'-(2-imidazoyl)urea having anticancer properties. A DNA modified nanometer-sized gold electrode was prepared by surface modification of a bare gold electrode using cysteamine. These electrodes have been characterized using electrochemical techniques and were used to study the interaction between DNA and the compound. Our results showed an increase in the adsorption peak current and a negative shift of E1/2 in the oxidation of ferrocyanide on cysteamine and DNA modified electrodes. For the interaction between the DNA and the compound having anticancer properties, a decrease in peak current of the oxidation of ferrocyanide was observed. The decrease in peak current is attributed to the shielding of the electroactive species by the compound intercalated to the DNA from reaching the electrode surface. Therefore, only few of the electroactive species are able to reach the electrode surface.